Home > Publications database > KKR- Greensche Funktionsmethode für das volle Zellpotential |
Book/Report | FZJ-2018-03398 |
1991
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/18861
Report No.: Juel-2445
Abstract: In the past, electronic structure calculations based on the Korringa-Kohn-Rostocker (KKR) method have been restricted to the use of muffin-tin potentials. In this work an extension of the KKR Green's function method to full cellular potentials is developed. By applying this new method, vacancy formation energies of all 3d- and 4d-transition metals as well as the electric-field gradients of dilute Cu-alloys with 3d- and 4sp-impurities are calculated. In the first part of this work this full potential method is described in detail. An important point for realistic calculations is the implementation of extremely efficient numerical techniques. The coupled radial equations for the wave functions are iteratively solved by treating the anisotropic part of the potential as pertubation and by expanding the wave functions into powers of this pertubation in the sense of a Born series. It is shown that this method is numerically stable, fast and easy to implement. For most applications the second Born approximation is already sufficient. Another important aspect is the description of the form of the aligner-Seitz cells by shape functions. In the second part applications of this method are presented. The calculated vacancy formation energies for Cu and Ag agree within 0.1 eV with the experiments. In view of greater experimental uncertainties for the other 3d- and 4d-metals a reasonable agreement is still found. For the dilute Cu-alloys the electric-field gradients (EFG) of Cu atoms next to 3d- and 4sp-impurities are calculated. It is shown that the dominant contribution to the EFGs of these Cu atoms arises from the Cu d-electrons. All previous calculations - mainly based onjellium models could not describe this effect.
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